drm/msm/dpu: remove NULL-ness check in dpu_hw_intr_destroy

There is no need to check that kfree() argument is not NULL. Remove
extra check and call kfree() unconditionally.

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://lore.kernel.org/r/20220507114009.1696278-1-dmitry.baryshkov@linaro.org


Signed-off-by: Rob Clark <robdclark@chromium.org>